Abstract P3-07-02: Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial

Background:

As compared to invasive breast cancer (IBC), HER2 is much more frequently overexpressed in ductal carcinoma in situ (DCIS). Unlike IBC, the prognostic significance of HER2 overexpression remains to be established in DCIS and large studies to investigate its predictive role are lacking. We investigated the prognostic and predictive relevance of HER2 protein and ERBB2 mRNA expression in DCIS using material from UK/ANZ DCIS trial.

Methods:

Formalin-fixed paraffin embedded tissues (FFPETs) were collected from patients enrolled in the UK/ANZ DCIS trial, a randomised 2X2 factorial design trial investigating role of tamoxifen, radiotherapy or both as adjuvant treatment in DCIS. ERBB2 mRNA expression was evaluated by reverse transcription followed by PCR on customized Taqman low-density arrays. ERBB2 mRNA expression was analysed as a continuous variable and also as a binary variable using a cut-off to reproduce HER2 expression distribution similar to that observed with immunohistochemistry (IHC). HER2 protein expression was evaluated by IHC using HercepTest™ and scored as per ASCO-CAP 2013 recommendations; HER2 equivocal (IHC2+) were grouped with HER2 negative (IHC 0 or 1+) for main analyses. Additional analyses using binary ERBB2 mRNA expression as a reflex test for HER2 IHC2+ were also performed.

Results:

HER2 protein expression was evaluable in 713 (181 events) of 755 available samples (DCIS absent or lost during assay in 42). ERBB2 mRNA expression was evaluable in 521 (134 events) of 704 available samples (DCIS absent or insufficient RNA in 51, assay failure in 132). Both results were available in 508 cases (130 events). Increase in ERBB2 mRNA expression (median 0.62; range 0.07-36.76) was associated with increased risk of in situ ipsilateral breast event (DCIS-IBE) [Hazard ratio (HR) = 1.07; 95% Confidence Interval (95%CI) 1.04-1.10; p < 0.0001] but not with increased risk of invasive ipsilateral breast event (I-IBE) [HR = 1.03; 95%CI 0.97-1.10; p = 0.3209]. HER2 positivity by IHC was similarly associated with increased risk of DCIS-IBE [HR = 2.90; 95%CI 1.91-4.40; p < 0.0001] but not with increased risk of I-IBE [HR = 1.40; 95%CI 0. 0.81-2.42; p = 0.2313]. Reclassification of HER2 IHC2+ cases using binary ERBB2 mRNA expression (46 as negative, 16 as positive; 18 expression data unavailable) further improved prognostic discrimination of HER2 IHC [ΔX2 (1d.f.) 5.51; p = 0.0189] for any recurrence. The effect of radiotherapy (RT) for reducing I-IBE was greater in HER2 positive (by ERBB2 mRNA expression) cases [HR = 0.24; 95%CI 0.07-0.83; p = 0.0237] as compared with HER2 negative cases [HR = 0.60; 95%CI 0.23-1.55; p = 0.2925]. Kaplan-Meier estimates of 10-year I-IBE rates with and without RT were 4.5% (2.5%-1.4%) and 15.8% (9.6%-25.3%) in HER2 positive DCIS; rates in HER negative DCIS were 5.2% (2.1%-2.4%) and 7.3% (4.3%-12.2%) respectively. The differential benefit of RT by HER2 status was also seen for reduction in DCIS-IBE.

Conclusions:

HER2 overexpression is associated with increased risk of DCIS-IBE but not of I-IBE. HER2 status is predictive of radiotherapy response with larger reductions in both I-IBE and DCIS-IBE seen in HER2 positive DCIS.

Citation Format: Thorat MA, Wagner S, Jones LJ, Levey PM, Bulka K, Hoff R, Sangale Z, Flake II DD, Bundred NJ, Fentiman IS, Forbes JF, Lanchbury JS, Cuzick J. Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-02.

Barriers to preventive therapy for breast and other major cancers and strategies to improve uptake

The global cancer burden continues to rise and the war on cancer can only be won if improvements in treatment go hand in hand with therapeutic cancer prevention. Despite the availability of several efficacious agents, utilisation of preventive therapy has been poor due to various barriers, such as the lack of physician and patient awareness, fear of side effects, and licensing and indemnity issues. In this review, we discuss these barriers in detail and propose strategies to overcome them. These strategies include improving physician awareness and countering prejudices by highlighting the important differences between preventive therapy and cancer treatment. The importance of the agent-biomarker-cohort (ABC) paradigm to improve effectiveness of preventive therapy cannot be overemphasised. Future research to improve therapeutic cancer prevention needs to include improvements in the prediction of benefits and harms, and improvements in the safety profile of existing agents by experimentation with dose. We also highlight the role of drug repurposing for providing new agents as well as to address the current imbalance between therapeutic and preventive research. In order to move the field of therapeutic cancer prevention forwards, engagement with policymakers to correct research imbalance as well as to remove practical obstacles to implementation is also urgently needed.

Impact of preventive therapy on the risk of breast cancer among women with benign breast disease

There are three main ways in which women can be identified as being at high risk of breast cancer i) family history of breast and/or ovarian cancer, which includes genetic factors ii) mammographically identified high breast density, and iii) certain types of benign breast disease. The last category is the least common, but in some ways the easiest one for which treatment can be offered, because these women have already entered into the treatment system. The highest risk is seen in women with lobular carcinoma in situ (LCIS), but this is very rare. More common is atypical hyperplasia (AH), which carries a 4-5-fold risk of breast cancer as compared to general population. Even more common is hyperplasia of the usual type and carries a roughly two-fold increased risk. Women with aspirated cysts are also at increased risk of subsequent breast cancer. Tamoxifen has been shown to be particularly effective in preventing subsequent breast cancer in women with AH, with a more than 70% reduction in the P1 trial and a 60% reduction in IBIS-I. The aromatase inhibitors (AIs) also are highly effective for AH and LCIS. There are no published data on the effectiveness of tamoxifen or the AIs for breast cancer prevention in women with hyperplasia of the usual type, or for women with aspirated cysts. Improving diagnostic consistency, breast cancer risk prediction and education of physicians and patients regarding therapeutic prevention in women with benign breast disease may strengthen breast cancer prevention efforts.

Letrozole-induced necrotising leukocytoclastic small vessel vasculitis: First report of a case in the UK

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Letrozole is a commonly used drug in breast cancer treatment.

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Letrozole induced cutaneous leukocytoclastic small vessel vasculitis: first UK case.

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There was extensive superficial skin necrosis; needed local and systemic steroids.

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Interestingly, the cancer shrank without treatment during the 3-4 month episode.

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Breast teams should be aware of this rare side effect.

Introduction

Letrozole, an aromatase inhibitor, is a commonly used neo-adjuvant drug to treat hormone-sensitive breast cancer. There have been a few cases of aromatase inhibitor induced vasculitis but the first case of letrozole-induced vasculitis was reported from Switzerland in 2014 (Digklia et al.) [1].

Presentation of case

We report the case of a 72-year-old woman with a small breast cancer. She was started on pre-operative letrozole (2.5 mg/d) whilst awaiting surgery. Ten days later she presented with burning pain and purpuric skin lesions which progressed to extensive ischaemic superficial necrosis of the lower limb skin, resolving over 3–4 months after local and systemic steroids. Histologically, it showed leucocytoclasis with evidence of eosinophilia consistent with a diagnosis of cutaneous leukocytoclastic small vessel vasculitis.

Discussion

The initial clinical presentation was severe burning pain around the ankles and a spreading violaceous rash. Letrozole was stopped. Wide local excision (lumpectomy) and sentinel node biopsy were postponed because of the accompanying pneumonitis and gastrointestinal upset, and were carried out 3.5 months later. Fortunately, the tumour size did not increase, but appeared to reduce, and axillary lymph nodes remained negative, i.e., this patient’s cancer outcome does not seem to have been jeopardized.

Conclusion

Leukocytoclastic vasculitis is a hypersensitivity reaction that is usually self-resolving, though our case needed systemic steroid treatment. Letrozole is a commonly used drug in clinical practice and prescribers should be aware of this rare side effect, which in our case delayed treatment without any apparent harm and possibly reduced tumour size.

Prophylactic use of aspirin: systematic review of harms and approaches to mitigation in the general population

A careful assessment of benefits and harms is required to assess suitability of aspirin as a prophylactic public health measure. However, comprehensive population-level data on harms are lacking. We collected and synthesized age and sex-specific data on harms relevant to aspirin use in average-risk individuals aged 50 years or older. We conducted systematic literature searches to identify baseline rates of gastrointestinal (GI) bleeding, peptic ulcer, major extra-cranial bleeding, and case-fatality rates due to GI bleeding or peptic ulcer in general population. The magnitude of aspirin-associated increase, the prevalence and attributable risk of Helicobacter pylori infection on these events in aspirin users was also assessed. Baseline rates of major extracranial bleeding events and GI complications increase with age; an almost threefold to fourfold increase is observed from age 50-54 to 70-74 years. Low or standard-dose aspirin use increases GI bleeding events by 60% leading to an annual excess of 0.45 and 0.79 GI bleeding events per 1,000 women and men aged 50-54 years respectively. 5-10% of major GI complications are fatal; a clear age dependence--higher fatality in older individuals, is seen. Eradication of H. pylori infection before aspirin use could reduce the incidence of upper GI complications by 25-30%. GI complications are increased by about 60% due to aspirin use but are fatal only in a very small proportion of individuals younger than 70 years of age. Major bleeding events that are comparable in severity to cancer or CVD, are infrequent. Screening and eradication of H. pylori infection could substantially lower aspirin-related GI harms.

Estimates of benefits and harms of prophylactic use of aspirin in the general population

BACKGROUND

Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population.

METHODS

The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer.

RESULTS

The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period.

CONCLUSIONS

Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

Prevention and early detection of prostate cancer

Prostate cancer is a common malignancy in men and the worldwide burden of this disease is rising. Lifestyle modifications such as smoking cessation, exercise, and weight control offer opportunities to reduce the risk of developing prostate cancer. Early detection of prostate cancer by prostate-specific antigen (PSA) screening is controversial, but changes in the PSA threshold, frequency of screening, and the use of other biomarkers have the potential to minimise the overdiagnosis associated with PSA screening. Several new biomarkers for individuals with raised PSA concentrations or those diagnosed with prostate cancer are likely to identify individuals who can be spared aggressive treatment. Several pharmacological agents such as 5α-reductase inhibitors and aspirin could prevent development of prostate cancer. In this Review, we discuss the present evidence and research questions regarding prevention, early detection of prostate cancer, and management of men either at high risk of prostate cancer or diagnosed with low-grade prostate cancer.

DNA methylation gene-based models indicating independent poor outcome in prostate cancer

BACKGROUND

Prostate cancer has a variable clinical behaviour with frequently unpredictable outcome. DNA methylation plays an important role in determining the biology of cancer but prognostic information is scanty. We assessed the potential of gene-specific DNA methylation changes to predict death from prostate cancer in a cohort of untreated men in the UK.

METHODS

This was a population-based study in which cases were identified from six cancer registries in Great Britain. DNA was extracted from formalin-fixed paraffin wax-embedded transurethral prostate resection tissues collected during 1990-96 from men with clinically-localised cancer who chose not to be treated for at least 6 months following diagnosis. The primary end point was death from prostate cancer. Outcomes were determined through medical records and cancer registry records. Pyrosequencing was used to quantify methylation in 13 candidate genes with established or suggested roles in cancer. Univariate and multivariate Cox models were used to identify possible predictors for prostate cancer-related death.

RESULTS

Of 367 men, 99 died from prostate cancer during a median of 9.5 years follow-up (max = 20). Univariately, 12 genes were significantly associated with prostate cancer mortality, hazard ratios ranged between 1.09 and 1.28 per decile increase in methylation. Stepwise Cox regression modelling suggested that the methylation of genes HSPB1, CCND2 and DPYS contributed objective prognostic information to Gleason score and PSA with respect to cancer-related death during follow-up (p = 0.006).

CONCLUSION

Methylation of 13 genes was analysed in 367 men with localised prostate cancer who were conservatively treated and stratified with respect to death from prostate cancer and those who survived or died of other causes. Of the 13 genes analysed, differential methylation of HSPB1, CCND2 and DPYS provided independent prognostic information. Assessment of gene-methylation may provide independent objective information that can be used to segregate prostate cancers at diagnosis into predicted behavioural groups.

Quantitative DNA methylation and recurrence of breast cancer: a study of 30 candidate genes

BACKGROUND

The need for new prognostic factors in breast cancer is ever increasing as breast cancer management evolves. Aberrant DNA methylation plays a pivotal role in cancer development and progression; DNA methylation-based biomarkers may provide independent prognostic information. We used pyrosequencing to investigate the prognostic potential of quantitative DNA methylation of a large set of candidate genes in a Korean single-institution series of operable breast cancer.

METHODS

Absolute DNA methylation in 20 candidate genes from an initial set of 30 genes was measured by pyrosequencing of bisulfite converted DNA in 121 fresh frozen breast cancer cases. Survival analyses used continuous and categorized (quintile-based) gene methylation data with time to recurrence (TTR) as an endpoint. Prognostic abilities of gene-only and risk-score models were explored.

RESULTS

Median follow-up was 5.1 years; 25 recurrences (21%) were observed. Nodal status, methylation of TWIST1, SLIT2 (both as continuous and categorized variables) and APC, HLA-A, NKX2-5, SERPINB5, SFN (as categorized variables) were significantly prognostic; grade showed a prognostic trend. A multivariate model containing nodal status, grade and TWIST1 was a best fit (p< 0.001) in stepwise regression; risk-score based on this model separated patients into 3 distinct risk-groups (p< 0.001). A gene-only model based on TWIST1 and SFN also classified patients into distinct risk-groups (p=0.009).

CONCLUSIONS

This study shows that accurate quantitative measurement of DNA methylation by pyrosequencing identifies a small set of genes with independent prognostic potential in breast cancer. These genes complement the current clinico-pathological prognostic factors and appear to be potential biomarkers that warrant further validation.

13-gene signature to predict rapid development of brain metastases in patients with HER2-positive advanced breast cancer

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Background: Brain metastases (BM) of breast cancer constitute an important part of therapeutic failures and are associated with severe morbidity and mortality. The risk of BM is particularly high in HER2+ advanced breast cancer pts. We earlier developed in this group a 13-gene signature strongly predicting for rapid development of BM (J Clin Oncol 2008; 26: 45s). Now, we validated these results in an independent group of pts and on culture model system. Methods: Discovery group included 87 samples analyzed using cDNA synthesis, annealing, selection, extension, ligation and array hybridization (DASL). Independent validation group included 75 samples analyzed using quantitative reverse-transcriptase PCR. 3D culture validation model system used immortal, non-tumorigenic human MCF10A breast epithelial cells with and without ectopic expression of HER-2 and RAD51, a DNA double strand break repair gene (one of the three genes of this group overexpressed in 13-gene signature). The number and morphology of breast acini were scored using indirect immunoflourescence and confocal microscopy. Results: Median brain metastasis-free survival (BMFS) in the discovery group for ‘high’ vs. ‘low’ expression signature tumors was 36 months and 66 months, respectively (P=0.0068), and in the validation group 54 and 86 months, respectively (P=0.032). Short BMFS was also associated with ER-negativity; BMFS in the cohort of ‘high’ 13-gene signature and ER- tumors vs. other 3 groups was 31 months and 66 months in discovery group, and 41 and 77 months in validation group (P<0.0001 and P=0.02, respectively). Overexpression of RAD51 in MCF-10A breast cells altered their three-dimensional acinar morphology and increased the percentage of invasive structures by 6.5 fold, both in the presence and absence of HER2 overexpression. Conclusions: 13-gene signature and ER-negativity predict rapid development of BM in HER+ advanced breast cancer pts. RAD51 may promote aggressiveness in breast epithelial cells. These data may be useful in the design of BM preventive trials and may prompt new treatment strategies.

Absolute quantitation of DNA methylation of 28 candidate genes in prostate cancer using pyrosequencing

Aberrant DNA methylation plays a pivotal role in carcinogenesis and its mapping is likely to provide biomarkers for improved diagnostic and risk assessment in prostate cancer (PCa). We quantified and compared absolute methylation levels among 28 candidate genes in 48 PCa and 29 benign prostate hyperplasia (BPH) samples using the pyrosequencing (PSQ) method to identify genes with diagnostic and prognostic potential.

RARB, HIN1, BCL2, GSTP1, CCND2, EGFR5, APC, RASSF1A, MDR1, NKX2-5, CDH13, DPYS, PTGS2, EDNRB, MAL, PDLIM4, HLAa, ESR1 and TIG1 were highly methylated in PCa compared to BPH (p < 0.001), while SERPINB5, CDH1, TWIST1, DAPK1, THRB, MCAM, SLIT2, CDKN2a and SFN were not. RARB methylation above 21% completely distinguished PCa from BPH. Separation based on methylation level of SFN, SLIT2 and SERPINB5 distinguished low and high Gleason score cancers, e.g. SFN and SERPINB5 together correctly classified 81% and 77% of high and low Gleason score cancers respectively. Several genes including CDH1 previously reported as methylation markers in PCa were not confirmed in our study. Increasing age was positively associated with gene methylation (p < 0.0001).

Accurate quantitative measurement of gene methylation in PCa appears promising and further validation of genes like RARB, HIN1, BCL2, APC and GSTP1 is warranted for diagnostic potential and SFN, SLIT2 and SERPINB5 for prognostic potential.

Role of glucocorticoids in breast cancer

Glucocorticoids play an essential role in embryonic development and tissue homeostasis and possess important anti-inflammatory and immunosuppressive properties. Due to their very wide spectrum of activity, Glucocorticoids are one of the most commonly used drugs-used in the treatment of asthma, arthritis, autoimmune diseases and shock/SIRS. glucocorticoids are a main component of treatment regimens in hematological malignancies due to their pro-apoptotic properties and are also used as co-treatment several other cancers and chemotherapy regimens including those in breast cancer treatment. In breast cancer, however, glucocorticoids may have diverse effects and could inhibit chemosensitivity. Additionally, glucocorticoids through their receptor may interact with ER in a feedback loop regulating each other's activities. The normal variation of glucocorticoid levels with time of the day, menstrual cycle or year could have a interesting chronobiological interaction with the well recorded variation in breast cancer proliferation and metastatic potential. Glucocorticoids could play a very complex role in breast cancer epidemiology, biology and treatment; this review aims to present a comprehensive discussion as well as speculate future directions for research.

The effects of oncotype DX recurrence scores on chemotherapy utilization in a multi-institutional breast cancer cohort

The use of clinicopathologic features in decision-making in early stage estrogen receptor (ER)-positive breast cancer (BC) may lead to over or under treatment. We investigated the effect of the Oncotype Dx (ODX) on chemotherapy (CTX) utilization in two cancer centers. 276 cases of node-negative ER-positive BC had ODX between 2005 and 2009. Age at diagnosis, tumor size, grade, and progesterone receptor (PR) status were abstracted from records and provided to two medical oncologists blinded to the ODX score. A recommendation for or against CTX was made based on clinicopathologic characteristics. Median age was 55 years. Mean tumor size was 1.6 cm. The median 10-year Adjuvant! Online (AO) mortality risk was 8. The median Nottingham Prognostic Index (NPI) was 3.3. The median ODX recurrence score was 17. Without knowledge of the ODX, oncologists were more likely to recommend CTX to younger women (P < 0.0001), women with negative PR status (P < 0.0001), higher NPI (P < 0.012), and tumors > 1 cm (P = 0.033). On average, CTX recommended patients had larger tumors (2.0 vs. 1.2 cm) and higher AO 10-year mortality (11.4 vs. 4.4%). ODX resulted in a change in management for 38% of women. Of 188 total patients who did not receive CTX, 71 had a recommendation favoring CTX by an oncologist blinded to the ODX score. In our multi-institutional cohort, the ODX score had a significant impact on the receipt of adjuvant CTX and altered management for 38% of women.

Expression of Forkhead-box protein A1, a marker of luminal A type breast cancer, parallels low Oncotype DX 21-gene recurrence scores

The Oncotype DX assay is one of the molecular tests that provide predictive and prognostic information to breast cancer patients with estrogen receptor (ER)-positive and node-negative disease. This study evaluates the association of Forkhead-box protein A1 (FOXA1) and GATA-binding protein 3 (GATA3) expressions with Oncotype DX recurrences scores in 77 cases of patients with ER-positive node-negative breast carcinomas diagnosed at Indiana University. The data were correlated with patient age, tumor size, histologic type, Scarff-Bloom-Richardson score, histologic grade, and progesterone receptor status. The median FOXA1 and GATA3 scores were 240 and 200, respectively. The Oncotype DX recurrence scores were low in 57%, intermediate in 30%, and high in 13% of cases. FOXA1 expression correlated negatively with Oncotype DX recurrence scores (P=0.004), and histologic type (P=0.0004). Oncotype DX recurrences score also correlated negatively with progesterone receptor (P=0.035) with 100% of progesterone receptor-negative cases having high or intermediate Oncotype DX scores. FOXA1 and GATA3 expressions correlated positively (P=0.014). The correlation between FOXA1 expression and Oncotype DX recurrence scores remained significant after adjusting for multiple comparisons and controlling for confounders such as histological type, grade, and progesterone receptor. A statistically significant correlation between the Oncotype DX recurrence scores and FOXA1 expression in our diverse cohort of ER-positive breast cancer patients was observed. We propose that this may represent a more cost-effective strategy to further risk stratify patients with good prognosis in whom chemotherapy may be omitted. To confirm these findings, further studies in a larger cohort of patients are warranted.

Differential subcellular expression of protein kinase C betaII in breast cancer: correlation with breast cancer subtypes

Protein kinase C betaII (PKCβII) represents a novel potential target for anticancer therapies in breast cancer. In order to identify patient subgroups which might benefit from PKC-targeting therapies, we investigated the expression of PKCβII in human breast cancer cell lines and in a tissue microarray (TMA). We first screened breast cancer cell line representatives of breast cancer subtypes for PKCβII expression at the mRNA and at the protein levels. We analyzed a TMA comprising of tumors from 438 patients with a median followup of 15.4 years for PKCβII expression by immunohistochemistry along with other prognostic factors in breast cancer. Among a panel of human breast cancer cell lines, only MDA-MB-436, a triple negative basal cell line, showed overexpression for PKCβII both at the mRNA and at the protein levels. In breast cancer patients, cytoplasmic expression of PKCβII correlated positively with human epidermal growth factor receptor-2 (HER-2; P = 0.01) and Ki-67 (P = 0.016), while nuclear PKCβII correlated positively with estrogen receptor (ER; P = 0.016). The positive correlation of CK5/6 with cytoplasmic PKCβII (P = 0.033) lost statistical significance after adjusting for multiple comparisons (P = 0.198). Cytoplasmic PKCβII did not correlate with cyclooxygenase (COX-2; P = 0.925) and vascular endothelial growth factor (P = 1). There was no significant association between PKCβII staining and overall survival. Cytoplasmic PKCβII correlates with HER-2 and Ki-67, while nuclear PKCβII correlates with ER in breast cancer. Our study suggests the necessity for assessing the subcellular localization of PKCβII in breast cancer subtypes when evaluating the possible effectiveness of PKCβII-targeting agents.

Prognosis of hormone-dependent breast cancers: implications of the presence of dysfunctional transcriptional networks activated by insulin via the immune transcription factor T-bet

Estrogen receptor alpha (ERalpha)-positive breast cancers that co-express transcription factors GATA-3 and FOXA1 have a favorable prognosis. These transcription factors form an autoregulatory hormonal network that influences estrogen responsiveness and sensitivity to hormonal therapy. Disruption of this network may be a mechanism whereby ERalpha-positive breast cancers become resistant to therapy. The transcription factor T-bet is a negative regulator of GATA-3 in the immune system. In this study, we report that insulin increases the expression of T-bet in breast cancer cells, which correlates with reduced expression of GATA-3, FOXA1, and the ERalpha:FOXA1:GATA-3 target gene GREB-1. The effects of insulin on GATA-3 and FOXA1 could be recapitulated through overexpression of T-bet in MCF-7 cells (MCF-7-T-bet). Chromatin immunoprecipitation assays revealed reduced ERalpha binding to GREB-1 enhancer regions in MCF-7-T-bet cells and in insulin-treated MCF-7 cells. MCF-7-T-bet cells were resistant to tamoxifen in the presence of insulin and displayed prolonged extracellular signal-regulated kinase and AKT activation in response to epidermal growth factor treatment. ERalpha-positive cells with intrinsic tamoxifen resistance as well as MCF-7 cells with acquired tamoxifen and fulvestrant resistance expressed elevated levels of T-bet and/or reduced levels of FOXA1 and GATA-3. Analysis of publicly available databases revealed ERalpha-positive/T-bet-positive breast cancers expressing lower levels of FOXA1 (P = 0.0137) and GATA-3 (P = 0.0063) compared with ERalpha-positive/T-bet-negative breast cancers. Thus, T-bet expression in primary tumors and circulating insulin levels may serve as surrogate biomarkers to identify ERalpha-positive breast cancers with a dysfunctional hormonal network, enhanced growth factor signaling, and resistance to hormonal therapy.

Prognostic impact of ALDH1 in breast cancer: a story of stem cells and tumor microenvironment

The concept of cancer cells being hierarchically organized and arising from their own progenitor stem cells will have important implications on cancer therapy. If this hypothesis were to be true then the paucity of estrogen receptors in stem cells as well as their inherent drug resistance mechanisms pose a challenge to current targeted therapies. In this study, we sought to examine the prognostic relevance of ALDH1, a putative cancer stem cell marker, by immunohistochemistry. The four cohorts analyzed included an adjuvantly treated series of 245 invasive cancers, a neoadjuvantly treated series of 34 cases, and two series of 58 and 40 triple negative cases, respectively. Both tumor cell and stromal expression for ALDH1 was evaluated, where possible. Tumor cell ALDH1 expression significantly correlated only with basal-like and HER2 tumor types in the adjuvant series and tumor grade in the neoadjuvant cohort. No significant enrichment for ALDH1 positive cells was observed in the postneoadjuvant therapy specimens compared to pretreatment samples. On the other hand, high degree of stromal expression was significantly associated with best disease-free survival as well as a trend for overall survival. The association of stromal expression was confirmed in an independent cohort of triple negative cases. The novel finding is that tumor microenvironment may play a significant role in determining the prognostic impact of stem/progenitor cells in human breast tumors.